Role of Thermally-Induced Buoyant Flow in Altering Energy Harvesting Using Geothermal Piles
Role of Thermally-Induced Buoyant Flow in Altering Energy Harvesting Using Geothermal Piles
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DOI：
10.1061/9780784480472.012
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发表时间：
2017-03
期刊：
影响因子：
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通讯作者：
Omid Ghasemi-Fare;P. Basu
中科院分区：
文献类型：
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作者：
Omid Ghasemi-Fare;P. Basu
本文提出了一个数值模型及其应用来分析地热桩周围饱和土壤中热致孔隙流体流动。考虑了热传导和对流对饱和土壤中换热器桩热性能的耦合影响。将传热能量方程和考虑 Boussinesq 浮力项的 Brinkman 动量方程耦合起来，分析通过孔隙流体流动的对流传热。有限差分求解方案采用显式-隐式混合方法来计算地面内的孔隙流体速度和温度增量。结果表明，地热桩的热运行改变了孔隙流体密度，换热器桩附近的饱和土壤中会发生浮力流（即使在静水条件下），饱和条件下的热致孔隙水流有利于桩-土的热交换。
This paper presents a numerical model and its application to analyze thermally induced pore fluid flow in saturated soil surrounding geothermal piles. Coupled effects of heat conduction and convection on thermal performance of heat exchanger piles in saturated soil are considered. Heat transfer energy equation and Brinkman’s momentum equation that considers a Boussinesq buoyancy term are coupled to analyze convective heat transfer through pore fluid flow. A hybrid explicit-implicit approach is employed in the finite difference solution scheme to calculate pore fluid velocity and temperature increments within the ground. Results indicate that thermal operation of geothermal piles alters pore fluid density, buoyant flow occurs (even under hydrostatic condition) within saturated soil in the vicinity of heat exchanger piles, and thermally induced pore water flow under saturated condition facilitates pile-soil heat exchange.